In Nepal, much emphasis has been given to the pollution of air, water, and solid waste both in terms of research and policymaking. Noise is an ignored pollutant, yet a growing public health concern in Kathmandu. This study is aimed at making an assessment of noise pollution in Kathmandu and study the effectiveness of the enforcement of noise standards and No Horn Regulation to control noise pollution. The study was conducted in 23 locations of four different zones (high traffic, low traffic, commercial, and residential) where 12 sites were considered for evaluating the effectiveness of No Horn Regulations. Noise level was studied at five different times of the day using a sound level meter to compute maximum, minimum, equivalent, and average noise level. This study concludes that (i) there is noise pollution problem in Kathmandu, (ii) No Horn Regulation is in place but it has not been strictly followed by the drivers and riders and monitored adequately by concerned authorities, and (iii) the regulation has been effective in reducing the noise level significantly. The average noise level of Kathmandu was recorded as 66.8 dB(A) with the highest noise level in High traffic zones, followed by commercial, low traffic, and residential zones. In 65.2% of the sampled sites, the noise level was beyond the permissible limit of WHO and National Sound Quality Standard of Nepal, 2012. Of the total honking events, 48.1% were against the provision of the No Horn Regulation. After the enforcement of the regulation, noise level was reduced significantly by 2.1 dB(A) in high traffic, low traffic, and residential zones. A comprehensive noise strategy with more emphasis on compliance monitoring and regular noise assessment should be formulated to address environmental noise as a major public health issue.

在尼泊尔，无论是在研究还是在政策制定方面，都非常重视空气，水和固体废物的污染。噪声是一种被忽略的污染物，但在加德满都却日益引起公众健康关注。这项研究旨在评估加德满都的噪声污染，并研究实施噪声标准和无喇叭法规以控制噪声污染的有效性。该研究在四个不同区域（高交通量，低交通量，商业和住宅）的23个地点进行，其中12个地点被认为是评估“无号角法规”的有效性。使用声级计在一天中的五个不同时间对噪声水平进行了研究，以计算最大，最小，等效和平均噪声水平。这项研究得出的结论是：（i）加德满都存在噪声污染问题，（ii）没有制定喇叭规章制度，但没有严格遵守驾驶员和骑车者的规定，并没有受到有关当局的充分监督；以及（iii）该规章制度已在有效降低噪音水平方面发挥了有效作用。加德满都的平均噪声水平记录为66.8 dB（A），在高流量区域中噪声水平最高，其次是商业，低流量和居民区。在65.2％的采样点中，噪声水平超出了WHO和尼泊尔国家声音质量标准（2012年）的允许极限。在总鸣喇叭事件中，有48.1％的声音违反了《无喇叭规定》。实施该法规后，在高交通量，低交通量和居民区中，噪声水平显着降低了2.1 dB（A）。